Display device

ABSTRACT

A driving circuit of a display device includes first to third output signal lines which are continuously arranged, a first transistor that has a source connected to the second output signal line and a drain connected to a first clock signal line, and a second transistor that provides a non-active potential to a gate of the first transistor when a second clock signal becomes the active potential, wherein a circuit that outputs the active potential to the first output signal line and the third output signal line is disposed at an opposite side to a circuit that outputs the active potential to the second output signal line with a display region interposed therebetween, and wherein the gate of the first transistor is connected to the first output signal line and the third output signal line via rectifying circuits.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese applicationJP2011-123747 filed on Jun. 1, 2011, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device.

2. Description of the Related Art

Liquid crystal displays are in wide use as display devices ofinformation communication terminals, such as a computer or a televisionset receiver. In addition, an organic EL display (OLED), a fieldemission display (FED), and the like are also known as flat paneldisplay devices . A liquid crystal display is a device in which thealignment of a liquid crystal composition sealed between two substratesis altered by changing an electric field and thus the extent oftransmission for light passing through the two substrates and the liquidcrystal composition is controlled, thereby displaying images.

In a display device, including the liquid crystal display, applying avoltage corresponding to a predetermined grayscale value to each pixelof a screen, pixel transistors for applying a voltage corresponding to agrayscale value to each pixel are disposed. Generally, gates of thepixel transistors for one line of the screen are connected to a signalline (hereinafter, referred to as a “scanning signal line”), and thescanning signal line is controlled by a driving circuit so as to outputan active voltage for turning on the pixel transistors sequentially lineby line. In addition, there is a display device having a bidirectionalscanning function capable of outputting the active voltage in both aforward direction and a backward direction so as to perform display byreversing upwards and downwards on the screen.

JP8-55493 A discloses a circuit for realizing bidirectional scanning,and switches for changing the forward direction and backward directionare provided for each line. JP2008-276849 A discloses an image displaydevice in which a circuit for performing the forward scanning isprovided at one end of each scanning signal line and a circuit forperforming the backward scanning is provided at the other end thereof inorder to realize the bidirectional scanning. The specification of U.S.Pat. No. 5,859,630 discloses a circuit capable of performingbidirectional scanning, disposed on one side of a display region.

SUMMARY OF THE INVENTION

In JP8-55493 A described above, two transistors are necessary for eachline in order to switch the scanning directions, and, in JP2008-276849A, driving circuits for performing scanning in the respective directionsat both sides of the display region are necessary. Therefore, the scaleof the circuit is inevitably increased. In addition, in thespecification of U.S. Pat. No. 5,859,630, the circuit capable ofperforming bidirectional scanning is disposed on one side of the displayregion, and thus the scale of a circuit on one side is increased. Inrecent years, there has been demand for reduction in a bezel regionwhich is a peripheral region of the display region, and an increase inthe scale of the circuit prevents a reduction in the bezel region andcauses an increase in power consumption.

The present invention has been made in consideration of thecircumstances, and an object thereof is to provide a display devicehaving a driving circuit which can perform bidirectional scanning andreduce the scale of the circuit.

According to an aspect of the present invention, there is provided adisplay device including a driving circuit that sequentially applies anactive potential for turning on a pixel transistor to a plurality ofoutput signal lines, wherein the driving circuit includes a first outputsignal line, a second output signal line, and a third output signal linethat are the plurality of output signal lines and are three outputsignal lines which are continuously arranged; a first clock signal lineto which a first clock signal which is a clock signal is applied; asecond clock signal line to which a second clock signal which is a clocksignal whose active potential does not temporally overlap the activepotential of the first clock signal is applied; a first transistor thatis a transistor of which one of the source and the drain is directly orindirectly connected to the second output signal line and the other ofthe source and the drain is directly or indirectly connected to thefirst clock signal line; and a second transistor that directly orindirectly provides a non-active potential to a gate of the firsttransistor when the second clock signal becomes the active potential,wherein a circuit that outputs the active potential to the first outputsignal line and the third output signal line is disposed at the oppositeside to a circuit that outputs the active potential to the second outputsignal line with a display region interposed therebetween, and whereinthe gate of the first transistor is directly or indirectly connected tothe first output signal line and the third output signal line viarectifying circuits, respectively.

In the display device according to the aspect of the present invention,the first output signal line may output the active potential when athird clock signal which is a clock signal whose active potential doesnot temporally overlap the active potential of the first and secondclock signals is applied thereto. In addition, the third output signalline may output the active potential when a fourth clock signal which isa clock signal whose active potential does not temporally overlap theactive potential of the first to third clock signals is applied thereto.Further, when the active potential is output in order of the firstoutput signal line, the second output signal line and the third outputsignal line, the first to fourth clock signals may be four-phase clockswhich become the active potential in order of the third clock signal,the first clock signal, the fourth clock signal and the second clocksignal, and, when the active potential is output in order of the thirdoutput signal line, the second output signal line and the first outputsignal line, the first to fourth clock signals may be four-phase clockswhich become the active potential in order of the fourth clock signal,the first clock signal, the third clock signal and the second clocksignal.

In the display device according to the aspect of the present invention,a transistor for voltage resistance whose gate is fixed to anintermediate voltage of which the absolute value is smaller than theactive potential may be provided between the gate of the firsttransistor and either of the source and the drain of the secondtransistor.

In the display device according to the aspect of the present invention,a transistor for voltage decrease whose gate is fixed to an intermediatevoltage of which the absolute value is smaller than the active potentialmay be provided between the second clock signal line and a gate of atransistor which outputs a low potential to the second output signalline during a period when the second output signal line does not outputthe active potential.

In the display device according to the aspect of the present invention,the first transistor and a transistor which outputs a low potential tothe second output signal line during a period when the second outputsignal line does not output the active potential may be divided by alast stage circuit block.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically illustrating a liquid crystal displayaccording to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a liquid crystalpanel.

FIG. 3 is a diagram schematically illustrating a configuration of adriving circuit.

FIG. 4 is a detailed diagram illustrating a circuit configuration of acircuit block of a left driving circuit.

FIG. 5 is a diagram illustrating a circuit configuration of an initialstage circuit block which is an initial stage of the circuit.

FIG. 6 is a diagram illustrating a circuit configuration of a last stagecircuit block which is a last stage of the circuit.

FIG. 7 is a diagram illustrating an operation timing chart when acircuit of the circuit block shown in FIG. 4 performs forward scanning.

FIG. 8 is a diagram illustrating an operation timing chart when acircuit of the circuit block shown in FIG. 4 performs backward scanning.

FIG. 9 is a diagram illustrating a circuit block which is a modifiedexample of the circuit block of the left driving circuit.

FIG. 10 is a diagram illustrating a circuit block which is a modifiedexample of the circuit block of the left driving circuit.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described withreference to the drawings. In addition, in the drawings, the same orequivalent elements are given the same reference numerals, and repeateddescription will be omitted.

FIG. 1 schematically shows a liquid crystal display 100 according to anembodiment of the present invention. As shown in this figure, the liquidcrystal display 100 includes an upper frame 110, a lower frame 120, aliquid crystal panel 200 fixed so as to be interposed therebetween, anda backlight device (not shown).

FIG. 2 shows a configuration of the liquid crystal panel 200 shown inFIG. 1. The liquid crystal panel 200 includes two substrates of a TFT(Thin Film Transistor) substrate 220 and a color filter substrate 230,and a liquid crystal composition is sealed between the substrates. TheTFT substrate 220 is provided with a driving circuit 210 whichsequentially applies a predetermined voltage to scanning signal lines G₁to G_(n) and a driving IC (Integrated Circuit) 260 which applies avoltage corresponding to a grayscale value of a pixel to a plurality ofdata signal lines (not shown) extending so as to intersect the scanningsignal lines G₁ to G_(n) in a pixel region 202 and controls the drivingcircuit 210. In addition, the driving circuit 210 includes a rightdriving circuit 212 located on the right side of the pixel region 202 inthe figure and a left driving circuit 214 located on the left side ofthe pixel region.

FIG. 3 is a diagram schematically illustrating a circuit configurationof the driving circuit 210. The right driving circuit 212 is a drivingcircuit which applies a high voltage (active voltage) for electricallyconnecting sources and drains of TFTs to gates of the TFTs disposed ateach pixel in relation to odd-numbered scanning signal lines G_(2i−1)(where i is a natural number) and the left driving circuit 214 is adriving circuit which applies a high voltage for electrically connectingsources and drains of TFTs to gates of the TFTs disposed at each pixelin relation to even-numbered scanning signal lines G_(2i). Except for astart signal VST, the right driving circuit 212 performs an output usingan output of the left driving circuit 214 as a trigger, and the leftdriving circuit 214 performs an output using an output of the rightdriving circuit 212 as a trigger. The right driving circuit 212 isdriven by clock signals CK1 and CK3, and the left driving circuit 214 isdriven by clock signals CK2 and CK4. In addition, the clock signals CK1to CK4 are four-phase clocks which become a high voltage in order ofCK1, CK2, CK3, and CK4 during forward scanning, and are four-phaseclocks which become an active voltage in order of CK4, CK3, CK2 and CK1during backward scanning.

The forward scanning starts by the right driving circuit 212 outputtinga high voltage to the scanning signal line G₁ and finishes by the leftdriving circuit 214 outputting a high voltage to the scanning signalline G_(n). The backward scanning starts by the left driving circuit 214outputting a high voltage to the scanning signal line G_(n) and finishesby the right driving circuit 212 outputting a high voltage to thescanning signal line G₁. In addition, the right driving circuit 212includes an initial stage circuit block 216 in the initial stage, aplurality of circuit blocks 213 outputting a high voltage to theodd-numbered scanning signal lines G_(2i−1), and a last stage circuitblock 217 in the last stage. The circuit blocks 213 receive signals ofthree consecutive even-numbered scanning signal lines G_(2i−2), G_(2i)and G_(2i+2), and output signals of two consecutive odd-numberedscanning signal lines G_(2i−1) and G_(2i|1). The left driving circuit214 includes an initial stage circuit block 216 in the initial stage, aplurality of circuit blocks 215 outputting a high voltage to theeven-numbered scanning signal lines G_(2i) and a last stage circuitblock 217 in the last stage. The circuit blocks 215 receive signals ofthree consecutive odd-numbered scanning signal lines G_(2i−1), G_(2i+1)and G_(2i+3), and output signals of two consecutive even-numberedscanning signal lines G_(2i) and G_(2i+2).

FIG. 4 shows a circuit configuration of the circuit block 215 of theleft driving circuit 214 in detail. Here, the names of the terminalsshown in FIG. 4 are changed not to the names of the terminals of thecircuit block 215 in FIG. 3 but to the names of the external terminalsof the driving circuit 210 in FIG. 3 in order to make a description withreference to the timing chart of FIG. 7 described later. As shown inFIG. 4, the circuit block 215 is a circuit operated by two clocks CK2and CK4, and shows two portions outputting a high voltage to twoscanning signal lines G_(2i) and G_(2i+2). In addition, the letter Tdenotes a transistor, and the letter N denotes a node. Further, eachtransistor is made of LTPS (Low Temperature Poly Silicon).

As shown in this figure, the circuit for outputting a high voltage tothe scanning signal line G_(2i)includes a diode transistor T1 which is arectifying circuit input during forward scanning, a transistor T2 whichfixes a gate electrode of a transistor T5 described later to a voltageVGL, a transistor T3 which charges a storage node N3, a storage nodereset transistor T4, the transistor T5 which outputs a high voltage tothe gate line, a transistor T6 which fixes the gate line to the voltageVGL using the storage node, a transistor T7 which resets the storagenode using an input signal during the forward scanning, an initial resettransistor T8, a transistor T9 for resetting the gate electrode of thetransistor T5, a voltage mitigation transistor T10 which restricts avoltage increased by the transistor T5 to an intermediate voltage VDH, atransistor T11 which decreases a voltage charged by the transistor T3 tothe intermediate voltage VDH, a diode transistor T12 which is arectifying circuit input during backward scanning, and a transistor T13which resets the storage node using an input signal during the backwardscanning. In addition, the intermediate voltage VDH turns on thetransistor, but is lower than the gate line high voltage VGH. In thedrawings, the intermediate voltage VDH and the voltage VGL are suffixedwith letter “L”. The letter L denotes belonging to left driving circuit214.

FIG. 5 shows a circuit configuration of the initial stage circuit block216 which is an initial stage of the circuit. The initial stage circuitblock 216 has a configuration where the initial reset transistor T8 isnot provided as compared with the circuit block 215.

FIG. 6 shows a circuit configuration of the last stage circuit block 217which is a last stage. The last stage circuit block 217 has aconfiguration where transistors T14 and T15 connected to inspectionterminals are further provided as compared with the circuit block 215.

In addition, FIG. 7 shows a timing chart of an operation of the circuitfor one stage of the circuit block 215 in FIG. 4 for outputting a highvoltage to the scanning signal line G_(2i). Hereinafter, an operation ofthe circuit in FIG. 4 will be described with reference to the timingchart of FIG. 7. First, in the circuit block 215, at the timing t1, thehigh voltage of the start signal VST_L is input to the left drivingcircuit 214 so as to set the voltage of the storage node N3 to be highas a reset operation. Next, at the timing t2, when the high voltage ofthe scanning signal line G_(2i−1) is input, the transistor T7 is firstturned on, in turn a low voltage VGL_L is applied to the node N3 suchthat the node N3 becomes the low voltage, the transistor T1 is turnedon, and the node N1 becomes a high voltage and is maintained thereat.Therefore, the node N2 becomes a high voltage via the transistor T10 ofwhich the gate is supplied with the intermediate voltage VDH, and thusthe transistor T5 is turned on.

Next, at the timing t3, when the clock signal CK2 becomes a highvoltage, the voltage of the node N2 which is the gate of the transistorT5 is further increased due to a so-called bootstrap effect, a highsignal is output to the scanning signal line G_(2i), and then a lowsignal is output thereto following an operation of the clock signal CK2.

Next, at the timing t4, when the clock signal CK4 becomes high, thetransistor T3 is turned on, the node N3 rises to a high level, and thetransistor T9 is turned on. Therefore, the node N1 falls to a low level.The node N1 makes the node N2 fall to a low level via the transistor T10so as to decrease the voltage between the source and the drain of thetransistor T2, and the transistor T6 is turned on by the high voltage ofthe node N3. Therefore, the scanning signal line G_(2i) is supplied witha low voltage VGL_L and is thus fixed to the low voltage.

Here, the transistor T10 has high voltage resistance as a double-gateconfiguration formed by overlapping two transistors so as to resist theincreased voltage due to the clock signal CK2 becoming high. The highsignal output to the scanning signal line G_(2i)is an input signal ofthe circuit block 213 of the right driving circuit 212, which outputs ahigh signal to the scanning signal line G_(2i+1) through an operationequivalent to the above-described operation.

FIG. 8 shows a timing chart when the circuit block 215 performs thebackward scanning from the scanning signal line G_(n) to the scanningsignal line G₁. Except that the phases of the clock signals CK1 to CK4differ and become high in reverse order, the timing chart duringbackward scanning is also the same as that during forward scanning.Hereinafter, an operation of the circuit in FIG. 4 will be describedwith reference to the timing chart of FIG. 8.

First, in the circuit block 215, at the timing t5, a high voltage of thestart signal VST_L is input to the left driving circuit 214 so as to setthe voltage of the storage node N3 to be high as a reset operation.Next, at the timing t6, when the high voltage of the scanning signalline G_(2i+1) is input, the transistor T13 is first turned on, a lowvoltage VGL_L is applied to the node N3 such that the node N3 becomesthe low voltage, in turn the transistor T12 is turned on, and the nodeN1 becomes a high voltage and is maintained thereat. Therefore, the nodeN2 becomes a high voltage via the transistor T10 of which the gate issupplied with the intermediate voltage VDH, and thus the transistor T5is turned on.

Next, at the timing t7, when the clock signal CK2 becomes a highvoltage, the voltage of the node N2 which is the gate of the transistorT5 is further increased due to a so-called bootstrap effect, a highsignal is output to the scanning signal line G_(2i), and then a lowsignal is output thereto following an operation of the clock signal CK2.

Next, at the timing t8, when the clock signal CK4 becomes high, thetransistor T3 is turned on, the node N3 rises to a high level, and thetransistor T9 is turned on. Therefore, the node N1 falls to a low level.The node N1 makes the node N2 fall to a low level via the transistor T10so as to decrease a voltage between the source and the drain of thetransistor T2, and the transistor T6 is turned on by the high voltage ofthe node N3. Therefore, the scanning signal line G_(2i) is supplied witha low voltage VGL_L and is thus fixed to the low voltage.

As described above, since, in the embodiment of the present invention,the driving circuit applying a high signal to the odd-numbered scanningsignal lines and the driving circuit applying a high signal to theeven-numbered scanning signal lines are disposed with the pixel regioninterposed therebetween, the scale of the circuit can be reduced to ahalf of the case where the driving circuit is disposed on one side ofthe pixel region, and thus the bezel region of the display device can bereduced.

In addition, since the circuit performing the forward scanning and thecircuit performing the backward scanning use the same circuit, a circuitperforming the backward scanning is not required to be disposed, andthus it is possible to reduce the scale of the circuit and to therebyreduce the bezel region of the display device.

In addition, since the circuit block has the double-gate configurationformed by overlapping transistors, a high voltage resistance circuit canbe formed even using LTPS.

FIG. 9 shows a circuit block 301 which is a modified example of thecircuit block 215 of the left driving circuit 214 according to theabove-described embodiment. A difference from the circuit block 215 isthat the transistor T8 is not provided, and the transistor T8 isprovided for charging the storage node N3 using the start signal VST_Lin the above-described embodiment. However, since all the clock signalsCK1 to CK4 become a high voltage and thereby the storage node N3 can becharged, it is possible to further reduce the scale of the circuit withthe configuration where the transistor T8 is not provided.

FIG. 10 shows a circuit block 302 which is a modified example of thecircuit block 215 of the left driving circuit 214 according to theabove-described embodiment. A difference from the circuit block 215 isthat the transistor T11 is not provided, and the transistor T11 isdisposed such that the high voltage of the clock signal CK4 is notdirectly applied to the gates of the transistors T2 and T6. However, ina case where a manufacturing line is suppressed from being contaminatedwith Na, it is possible to further reduce the scale of the circuit withthe configuration where the transistor T11 is not provided.

In addition, although the above-described embodiment uses an NMOS typetransistor whose source and drain are electrically connected to eachother by inputting a high voltage to a gate thereof as an activevoltage, a PMOS type transistor whose source and drain are electricallyconnected to each other by inputting a low voltage to the gate thereofas an active voltage may be used.

Further, although, in the above-described embodiment, the clock signalsuse four kinds of four-phase clocks, other two or more kinds of clocksignals may be used.

The liquid crystal display according to the respective embodiments maybe applied to liquid crystal displays of any type of an IPS (In-PlaneSwitching) type, a VA (Vertically Aligned) type, and a TN (TwistedNematic) type. In addition, the present invention is not limited to theliquid crystal display, and may be applied to an organic EL display, afield emission display (FED) , and other display devices using thedriving circuit.

While there have been described what are at present considered to becertain embodiments of the invention, it will be understood that variousmodifications may be made thereto, and it is intended that the appendedclaim cover all such modifications as fall within the true spirit andscope of the invention.

What is claimed is:
 1. A display device comprising: a plurality ofpixels including a pixel transistor respectively, a plurality ofscanning signal lines supplying a scanning signal to the plurality ofpixels respectively, a driving circuit sequentially applying thescanning signal to the plurality of scanning lines, and four clocksignal lines including a first clock signal line, a second clock signalline, a third clock signal line and a fourth clock signal line, whereinthe scanning signal has an active potential which is able to turn on apixel transistor and the non-active potential which is able to turn offthe pixel transistor, wherein the plurality of scanning signal lines arearranged in order of a first scanning signal line, a second scanningsignal line and a third scanning signal line, wherein the drivingcircuit comprises a first output circuit configured to output the activepotential to the first scanning signal line, wherein four clock signallines become the active potential in order of the first clock signalline, the second clock signal line, the third clock signal line and thefourth clock signal line, wherein a period of the active potential offour clock signal lines are not overlapped each other, wherein the firstoutput circuit comprises a first output transistor, the first outputtransistor has a gate, a source and a drain, the gate of the firstoutput transistor is connected to a first node, one of the source andthe drain of the first output transistor is connected to the firstscanning signal line for outputting the active potential to the firstscanning signal line and the other of the source and the drain isconnected to the second clock signal line, and when the first node isthe active potential, the first output transistor outputs the secondclock signal to the first scanning signal line; and wherein the firstoutput circuit further comprises a first reset transistor, the firstreset transistor provides the non-active potential to the gate of thefirst output transistor when the fourth clock signal becomes the activepotential.
 2. The display device according to claim 1, wherein the firstoutput circuit further comprises a second output transistor, the secondoutput transistor has a gate, a source and a drain, the gate of thesecond output transistor is connected to the fourth clock signal line,one of the source and the drain of the second output transistor isconnected to the first scanning signal line for outputting thenon-active potential to the first scanning signal line and the other ofthe source and the drain is connected to a non-active potential line,and when the fourth clock signal becomes the active potential, thesecond output transistor outputs the non-active potential to the firstscanning signal line.
 3. The display device according to claim 2,wherein the first output circuit further comprises a second resettransistor, wherein the second reset transistor connects between thegate of the second output transistor and the non-active potential line,the second reset transistor provides the non-active potential to thegate of the second output transistor when the first node becomes theactive potential.
 4. The display device according to claim 1, whereinthe driving circuit further comprises a third output circuit, whereinthe third output circuit configured to output the active potential tothe third scanning signal line, wherein the third output circuitcomprises the first output transistor and the first node like as thefirst output circuit, and wherein the second scanning signal line isconnected to the first node of the first output circuit and the thirdoutput circuit .
 5. The display device according to claim 4, wherein theactive potential of the second scanning signal line is applied to thefirst node of the first output circuit when a voltage of the first nodeof the first output circuit is active potential.
 6. A display devicecomprising: a plurality of pixels including a pixel transistorrespectively, a plurality of scanning signal lines supplying a scanningsignal to the plurality of pixels respectively, a driving circuitsequentially applying the scanning signal to the plurality of scanninglines, and four clock signal lines including a first clock signal line,a second clock signal line, a third clock signal line and a fourth clocksignal line, wherein the scanning signal has an active potential whichis able to turn on a pixel transistor and the non-active potential whichis able to turn off the pixel transistor, wherein the plurality ofscanning signal lines are arranged in order of a first scanning signalline, a second scanning signal line and a third scanning signal line,wherein the driving circuit comprises a first output circuit configuredto output the active potential to the first scanning signal line and athird output circuit configured to output the active potential to thethird scanning signal line, wherein, four clock signal lines become theactive potential in order of the first clock signal line, the secondclock signal line, the third clock signal line and the fourth clocksignal line, wherein a period of the active potential of four clocksignal lines are not overlapped each other, wherein the first outputcircuit and the third output circuit comprise a first output transistorrespectively, the first output transistor has a gate, a source and adrain, the gate of the first output transistor is connected to a firstnode, wherein one of the source and the drain of the first outputtransistor of the first output circuit is connected to the firstscanning signal line for outputting the active potential to the firstscanning signal line and the other of the source and the drain isconnected to the second clock signal line, and when the first node isthe active potential, the first output transistor of the first outputcircuit outputs the second clock signal to the first scanning signalline; wherein one of the source and the drain of the first outputtransistor of the third output circuit is connected to the thirdscanning signal line for outputting the active potential to the thirdscanning signal line and the other of the source and the drain isconnected to the fourth clock signal line, and when the first node isthe active potential, the first output transistor of the third outputcircuit outputs the fourth clock signal to the first scanning signalline; and wherein the first output circuit and the third output circuitfurther comprises a first reset transistor respectively, the first resettransistor of the first output circuit provides the non-active potentialto the gate of the first output transistor of the first output circuitwhen the fourth clock signal becomes the active potential, the firstreset transistor of the third output circuit provides the non-activepotential to the gate of the first output transistor of the third outputcircuit when the second clock signal becomes the active potential. 7.The display device according to claim 6, wherein the first outputcircuit and the third output circuit further comprise a second outputtransistor respectively, wherein the second output transistor has agate, a source and a drain, the gate of the second output transistor isconnected to the fourth clock signal line, one of the source and thedrain of the second output transistor is connected to the first scanningsignal line for outputting the non-active potential to the firstscanning signal line and the other of the source and the drain isconnected to a non-active potential line, and when the fourth clocksignal becomes the active potential, the second output transistoroutputs the non-active potential to the first scanning signal line. 8.The display device according to claim 6, wherein the first outputcircuit further comprises a second reset transistor, wherein the secondreset transistor connects between the gate of the second outputtransistor and the non-active potential line, the second resettransistor provides the non-active potential to the gate of the secondoutput transistor when the first node becomes the active potential. 9.The display device according to claim 6, wherein the second scanningsignal line is connected to the first node of the first output circuitand the third output circuit.
 10. The display device according to claim9, wherein the active potential of the second scanning signal line isapplied to the first node of the first output circuit when a voltage ofthe first node of the first output circuit is active potential.